#include "keyboard.h"
#include "print.h"
#include "interrupt.h"
#include "io.h"
#include "global.h"
#include "ioqueue.h"

#define KBD_BUF_PORT 0x60 // 键盘buffer寄存器端口号为0x60

/* 用转义字符定义部分控制字符 */
#define esc '\033' // 八进制表示字符,也可以用十六进制'\x1b'
#define backspace '\b'
#define tab '\t'
#define enter '\r'
#define delete '\177' // 八进制表示字符,十六进制为'\x7f'

/* 以上不可见字符一律定义为0 */
#define char_invisible 0
#define ctrl_l_char char_invisible
#define ctrl_r_char char_invisible
#define shift_l_char char_invisible
#define shift_r_char char_invisible
#define alt_l_char char_invisible
#define alt_r_char char_invisible
#define caps_lock_char char_invisible

/* 定义控制字符的通码和断码 */
#define shift_l_make 0x2a
#define shift_r_make 0x36
#define alt_l_make 0x38
#define alt_r_make 0xe038
#define alt_r_break 0xe0b8
#define ctrl_l_make 0x1d
#define ctrl_r_make 0xe01d
#define ctrl_r_break 0xe09d
#define caps_lock_make 0x3a

struct ioqueue kbd_buf;

/* 定义以下变量记录相应键是否按下的状态,
 * ext_scancode用于记录makecode是否以0xe0开头 */
static bool ctrl_status, shift_status, alt_status, caps_lock_status, ext_scancode;

/* 以通码make_code为索引的二维数组 */
static char keymap[][2] = {
    /* 扫描码   未与shift组合  与shift组合*/
    /* ---------------------------------- */
    /* 0x00 */ {0, 0},
    /* 0x01 */ {esc, esc},
    /* 0x02 */ {'1', '!'},
    /* 0x03 */ {'2', '@'},
    /* 0x04 */ {'3', '#'},
    /* 0x05 */ {'4', '$'},
    /* 0x06 */ {'5', '%'},
    /* 0x07 */ {'6', '^'},
    /* 0x08 */ {'7', '&'},
    /* 0x09 */ {'8', '*'},
    /* 0x0A */ {'9', '('},
    /* 0x0B */ {'0', ')'},
    /* 0x0C */ {'-', '_'},
    /* 0x0D */ {'=', '+'},
    /* 0x0E */ {backspace, backspace},
    /* 0x0F */ {tab, tab},
    /* 0x10 */ {'q', 'Q'},
    /* 0x11 */ {'w', 'W'},
    /* 0x12 */ {'e', 'E'},
    /* 0x13 */ {'r', 'R'},
    /* 0x14 */ {'t', 'T'},
    /* 0x15 */ {'y', 'Y'},
    /* 0x16 */ {'u', 'U'},
    /* 0x17 */ {'i', 'I'},
    /* 0x18 */ {'o', 'O'},
    /* 0x19 */ {'p', 'P'},
    /* 0x1A */ {'[', '{'},
    /* 0x1B */ {']', '}'},
    /* 0x1C */ {enter, enter},
    /* 0x1D */ {ctrl_l_char, ctrl_l_char},
    /* 0x1E */ {'a', 'A'},
    /* 0x1F */ {'s', 'S'},
    /* 0x20 */ {'d', 'D'},
    /* 0x21 */ {'f', 'F'},
    /* 0x22 */ {'g', 'G'},
    /* 0x23 */ {'h', 'H'},
    /* 0x24 */ {'j', 'J'},
    /* 0x25 */ {'k', 'K'},
    /* 0x26 */ {'l', 'L'},
    /* 0x27 */ {';', ':'},
    /* 0x28 */ {'\'', '"'},
    /* 0x29 */ {'`', '~'},
    /* 0x2A */ {shift_l_char, shift_l_char},
    /* 0x2B */ {'\\', '|'},
    /* 0x2C */ {'z', 'Z'},
    /* 0x2D */ {'x', 'X'},
    /* 0x2E */ {'c', 'C'},
    /* 0x2F */ {'v', 'V'},
    /* 0x30 */ {'b', 'B'},
    /* 0x31 */ {'n', 'N'},
    /* 0x32 */ {'m', 'M'},
    /* 0x33 */ {',', '<'},
    /* 0x34 */ {'.', '>'},
    /* 0x35 */ {'/', '?'},
    /* 0x36	*/ {shift_r_char, shift_r_char},
    /* 0x37 */ {'*', '*'},
    /* 0x38 */ {alt_l_char, alt_l_char},
    /* 0x39 */ {' ', ' '},
    /* 0x3A */ {caps_lock_char, caps_lock_char}
    /*其它按键暂不处理*/
};

/* 键盘中断处理程序 */
static void intr_keyboard_handler(void)
{
   /* 这次中断发生前的上一次中断,以下任意三个键是否有按下 */
   bool ctrl_down_last = ctrl_status;
   bool shift_down_last = shift_status;
   bool caps_lock_last = caps_lock_status;

   bool break_code;
   uint16_t scancode = inb(KBD_BUF_PORT);

   /* 若扫描码是e0开头的,表示此键的按下将产生多个扫描码,
    * 所以马上结束此次中断处理函数,等待下一个扫描码进来*/
   if (scancode == 0xe0)
   {
      ext_scancode = true; // 打开e0标记
      return;
   }

   /* 如果上次是以0xe0开头,将扫描码合并 */
   if (ext_scancode)
   {
      scancode = ((0xe000) | scancode);
      ext_scancode = false; // 关闭e0标记
   }

   break_code = ((scancode & 0x0080) != 0); // 获取break_code

   if (break_code)
   { // 若是断码break_code(按键弹起时产生的扫描码)

      /* 由于ctrl_r 和alt_r的make_code和break_code都是两字节,
      所以可用下面的方法取make_code,多字节的扫描码暂不处理 */
      uint16_t make_code = (scancode &= 0xff7f); // 得到其make_code(按键按下时产生的扫描码)

      /* 若是任意以下三个键弹起了,将状态置为false */
      if (make_code == ctrl_l_make || make_code == ctrl_r_make)
      {
         ctrl_status = false;
      }
      else if (make_code == shift_l_make || make_code == shift_r_make)
      {
         shift_status = false;
      }
      else if (make_code == alt_l_make || make_code == alt_r_make)
      {
         alt_status = false;
      } /* 由于caps_lock不是弹起后关闭,所以需要单独处理 */

      return; // 直接返回结束此次中断处理程序
   }
   /* 若为通码,只处理数组中定义的键以及alt_right和ctrl键,全是make_code */
   else if ((scancode > 0x00 && scancode < 0x3b) ||
            (scancode == alt_r_make) ||
            (scancode == ctrl_r_make))
   {
      bool shift = false; // 判断是否与shift组合,用来在一维数组中索引对应的字符
      if ((scancode < 0x0e) || (scancode == 0x29) ||
          (scancode == 0x1a) || (scancode == 0x1b) ||
          (scancode == 0x2b) || (scancode == 0x27) ||
          (scancode == 0x28) || (scancode == 0x33) ||
          (scancode == 0x34) || (scancode == 0x35))
      {
         /****** 代表两个字母的键 ********
             0x0e 数字'0'~'9',字符'-',字符'='
             0x29 字符'`'
             0x1a 字符'['
             0x1b 字符']'
             0x2b 字符'\\'
             0x27 字符';'
             0x28 字符'\''
             0x33 字符','
             0x34 字符'.'
             0x35 字符'/'
         *******************************/
         if (shift_down_last)
         { // 如果同时按下了shift键
            shift = true;
         }
      }
      else
      { // 默认为字母键
         if (shift_down_last && caps_lock_last)
         { // 如果shift和capslock同时按下
            shift = false;
         }
         else if (shift_down_last || caps_lock_last)
         { // 如果shift和capslock任意被按下
            shift = true;
         }
         else
         {
            shift = false;
         }
      }

      uint8_t index = (scancode &= 0x00ff); // 将扫描码的高字节置0,主要是针对高字节是e0的扫描码.
      char cur_char = keymap[index][shift]; // 在数组中找到对应的字符

      /* 只处理ascii码不为0的键 */
      if (cur_char)
      {
         if ((ctrl_down_last && cur_char == 'l') || (ctrl_down_last && cur_char == 'u')) {
            cur_char -= 'a';
         }
         if (!ioq_full(&kbd_buf))
         {
            //put_char(cur_char);
            ioq_putchar(&kbd_buf, cur_char);
         }
         return;
      }

      /* 记录本次是否按下了下面几类控制键之一,供下次键入时判断组合键 */
      if (scancode == ctrl_l_make || scancode == ctrl_r_make)
      {
         ctrl_status = true;
      }
      else if (scancode == shift_l_make || scancode == shift_r_make)
      {
         shift_status = true;
      }
      else if (scancode == alt_l_make || scancode == alt_r_make)
      {
         alt_status = true;
      }
      else if (scancode == caps_lock_make)
      {
         /* 不管之前是否有按下caps_lock键,当再次按下时则状态取反,
          * 即:已经开启时,再按下同样的键是关闭。关闭时按下表示开启。*/
         caps_lock_status = !caps_lock_status;
      }
   }
   else
   {
      put_str("unknown key\n");
   }
}

/* 键盘初始化 */
void keyboard_init()
{
   put_str("keyboard init start\n");
   ioqueue_init(&kbd_buf);
   register_handler(0x21, intr_keyboard_handler);
   put_str("keyboard init done\n");
}